Not to stir the pot but I do have a question. In another thread J.V. mentioned that a service could be extended to an outbuilding with 3 wires as long as it was tapped off at the meter or before any bonding takes place. I'm getting very confused as to what the difference is.

Yep, I'm not sure what is going on, one of those wires is probably the gec for one of the electrodes.

There are 200 amp meter sockets that have provisions (lugs) on the load terminals for 100 amp sub-feeds. I'm not sure what the situation was where J.V. mentioned this, but normally these sub-feeds are permitted on rural agricultural properties.

The code reference is 230.40 exception 3

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" One nice thing about the NEC articles ... you have lots of choices"

A question I have is, according to the articles here, it's OK to send a 3 wire feed to the barn under 2005 rules. In 2008 rules, it's not ok anymore. I know this statement doesn't change the safety of the situation... but electricity has been around for a long time. They didn't figure out that breakers wouldn't trip unless a ground wire was ran until after 2008?

No, you're still misunderstanding the circuitry here. The configuration you have installed WAS NEVER CODE COMPLIANT, AND NEVER SAFE! A three-wire feeder WITH NEUTRAL AND GROUND BONDED IN THE NEW PANEL was allowed until 2008, and only if it originated from the service equipment, not from a subpanel. That's essentially just an extension of the utility's drop to your property. Even though it's no longer allowed, I wouldn't object to that - it's safe as long as the neutral conductor remains intact.

It has NEVER been legal, accepted, or safe, to have a grounding system that is not bonded to neutral. This is a critical distinction. This is what you have installed. This is what Stubbie was explaining the perils of. All equipment grounding conductors MUST BE BONDED TO NEUTRAL SOMEWHERE.

You really need to get your head around the concept of bonding vs. grounding. Does someone have a convenient link to a Mike Holt thingy about this?

I don't know if you all have convinced the OP yet, but I for one greatly appreciate this conversation. It has really helped me understand why the ground and neutral need to be isolated in a sub-panel. Thank-you all!

I don't know if you all have convinced the OP yet, but I for one greatly appreciate this conversation. It has really helped me understand why the ground and neutral need to be isolated in a sub-panel. Thank-you all!

Dan

You know what...if somebody learns something from all of this then it's worth it. Glad we could help you.

The Following User Says Thank You to Missouri Bound For This Useful Post:

In an effort to show a comparison of the the 'barn' panel in this thread I have two diagrams.

The first diagram shows the Op's barn panel as it is presently wired only I left out the house sub panels he has to avoid confusion. I simply am showing a service equipment panel with a 3 wire feeder going to a panel in a detached building ... barn if you like....

The second diagram is a properly bonded 3 wire feeder that allows fault current to utilize the 'feeder' neutral to get back to the source transformer so that a breaker will trip. Understand that the bonding jumper (just like the one in the OPs barn panel) has been installed on the neutral bar in my drawing ... the ground bar is simply bonded to the metal enclosure by means of the mounting screws as it is not on insulated stand offs like the neutral bar but has metal to metal contact. The fault path includes the metal of the panel due to this bonding.

Quote:

Note that in the OPs barn panel both the grounding bar and the neutral bar are on insulated standoffs effectively isolating them from the metal of the enclosure and therefore both must have bonding jumpers like the one he has on the grounding bar in order for fault current to get to the feeder neutral to return to the source.

Attached Thumbnails

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I hadn't noticed this before. I had thought the service conductors were entering from the left but now I guess they are entering from the top along with the grounding electrode conductors?

Yep that's correct, I'm assuming those are gec's but who knows .... the op is finished with us. He just couldn't believe we know what we are talking about in his installation. It's a shame cause he has a real potential of getting someone killed the way he has the panels bonded.

His biggest problem is he thinks the connection to ground (earth) is what the breakers need to trip on fault.

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" One nice thing about the NEC articles ... you have lots of choices"